With his fabrication wizard brother at the helm, Brad was completely immersed in his third phase of development with his ‘64 Corvette. This time, it would enjoy the pleasures and suffer the pains of forced induction.
Brad’s done quite a lot with this build since he first bought it in 2016. At the beginning, it had a non-original, period correct 327 with a Muncie 4-speed in it. Brad took the car on the Power Tour in 2018 and long-hauled it, but oiling issues ate the heads up and he and his brother decided to build a 383 for it.
In the second phase of development, the 383 was assembled and combined with a Holley Sniper, a TKO-600, and (thankfully) Vintage Air air conditioning. They hauled it on the HRPT again in 2019, and then we did the Emerald Coast Cruzin’ in Panama City Beach, Florida, in fall 2019.
This January, they decided to take on a herculean task and fit the 383 with a pair of turbos. They were aware that a set of snails feeding the 383 would make more than 1,000 horsepower, although they set their sights on a more conservative 800 or so as this would better suit the aging chassis.
The block accommodates a hydraulic roller setup with LS7 lifters. The bottom end is a forged GM aftermarket crank which should support 1400-1500 horepower. The cam is a custom Comp grind. Heads are World Products Torquer S/R with big valves and a bit of port work, but nothing major. Compression on the motor is right at 9:1. The intake is a Weiand low-rise single plane that accommodates direct port EFI, which is managed by Holley HP. The throttle body is a Holley 4150 1000cfm unit. Injectors are Siemens 80lb. The distributor, the same one used with the Holley Sniper in the last iteration of this car, is a Holley Hyperspark.
To quench the block’s thirst, Brad opted for a 450lph in-tank pump with an Aeromotive regulator inside a Holley tank made for EFI in a midyear Corvette. With these choice parts used and the greater demands on the fuel system, it made sense to use new fuel lines and return lines. There are things you don’t skimp on at this level of investment.
Keeping the lump cool would require a little of Brad’s brother’s ingenuity. Using a big Spal fan with a custom shroud, which they could add with ease; the bay in a midyear Corvette is accommodating.
Which made life easier when building the engine’s hat. They had visions of something between an old-school Buick air cleaner and the period correct mechanical fuel injection setup. The hat houses air-to-water intercooler cores on each side that are fed by the turbos. Blow off valves are mounted on the front of the hat.
Then came time to fit the log manifolds, the turbos, and all the associated plumbing. Turbos are 61mm Precision, with Precision wastegates and BOVs. Higher boost will come later with a new chassis and larger tires to support it.
Fabbing the exhaust didn’t change much with the addition of the turbos. Before they were added, the 383 ran Hooker side exit full-length headers that mated up to a factory style side exhaust pipe. Obviously, those went with the addition of log-style manifolds, and along with them came Sweet Thunder pipes with a 3” case and 2.5” inner diameter.
They toyed with several alternatives to better support the forced induction setup, but ultimately decided the best option would be a set of QTP electric cutouts mounted along the down pipe and under the car. Hopefully now Brad will have a car that’s a little quieter at cruise and on the highway, but can transform into something intimidating at the touch of a button.
A trip to the dyno revealed numbers that were reasonable and acceptable at 9.5psi—probably no less than what should’ve been expected. No changes to fueling or timing resulted in additional power at that boost level, so it was likely the tuning was maxed out where it was. Ultimately, they ended up with 600 horsepower and 700 lb-ft of torque to the tires, which, while conservative, is much more than the current car can truly handle—even with the Viking coilovers aiding traction.
Brad knows there’s more potential there, but to harness it would require a retrofit with the modern chassis underneath—likely one with C5 or C6 suspension components. When they do, they will likely switch to a set of aluminum heads that will flow better and allow them to carry power further into higher revs.
To keep tabs and read deeper on this uncommon build, please visit Brad’s thread here.
